Platform leveling mechanism



Aug. 19, 1958 v. A. SANDERS 2,848,069

PLATFORM LEVELING MECHANISM Filed July 26, 1956 1 V NTOR. Val/yin "dd/S 'Fig4 z W 2,848,069 PLATFORM LEVELING'MECHANISM Vaughn A. Sanders, Spokane, Wasln, assignor to Pigeon Hole Parking, Inc., Spokane, Wash, a corporation of -Washington Application July 26, 1956, Serial No. 600,282

4 Claims. (Cl. 187-76) This-invention relates to elevators and more particulat-1y to a mechanism for leveling "elevators at the several delivery levels thereof.

Under present day practice in the operation of elevators, much has been done in attempting to bring an elevator to an exact horizontal alignment with relationto .pl-atform at the delivery floor level.

Heretofore, it has been common to provide ledges or stops at the desired levels and then employ horizontally extending lingers or latches'to cooperate with these stops, aud'also it is known to employ depending iatch fingers which are pivotly secured to an elevator platform at their upper ends and swingoutwardly at their lower ends over the projecting stops.

In each of these structures it is necessary that the elevator platform be raised above the desired level, the latch mechanism be actuated outwardly a commensurate amount to contact the stops and then the elevator be lowered to the level where the. platform is supported upon the latches by the stops. Obviously, considerable time of Operation is wasted to raise theplatform higher "than the delivery level and reverse its directionand lower it easily upon the stops.

The present invention seeks to overcome the unde- 'sirable features oflth'e heretofore known structures, and

provides means for leveling a platform which includes cooperating notched cam plates and latch wheels which are moved into platform supporting engagement relative to each other by means of prime movers such as a plurality of fluid pressure motors.

It will thus be seen during a study of the subsequent detailed description of the invention that the platform will be raised or lowered to ,the approximate plane level at the delivery floor desired and then the leveling mechanism will be actuated to support and level the platform at the desired level. Any small differentials because of the deflection of the platform will thus be compensated for, and any small displacement from the horizontal plane of the platform because ofstretchin'g cables or other mechanical discrepancies will also find compensation through the actuation of the leveling mechanism constituting the subject matter of "this invention.

The objects and advantages of the invention herein before disclosed and others will become more apparent during the course of the following description.

In the accompanying drawing, forming a part of this specification in which like numerals are employed to designate like parts:

ice

Figure l is a horizontal cross section through an elevator showing the top surface of the elevator platform in plan and vertical guide post members of the elevator structure in cross section with the platform leveling mechanisms associated therewith;

Figur'e2 is an enlarged vertical side elevation of one corner of the elevator showing one of the plural platform leveling mechanisms and the fluid pressure system associated therewith in a diagrammatic manner;

Figure 3-is a fragmentary plan view of one of the improved, platform leveling mechanisms;

Figure 4is a vertical longitudinal cross section taken on the plane indicated by the lines 4-4 of Figure 3;

and

Figure 5 is a fragmentary face view of the notched "cam plate adjustably secured to a frame member of the elevator.

Referring now more particularly to the drawings, I

have shown .an elevator frame having vertical guide post members 10 at the four corners of the frame. It will be understood that the elevator may be astationary struction and is not limited to a guide frame'having corner vertical guide posts 10, but the scope of the invention is applicable to the broad and varied field 'of vertically moveable elevator platforms.

Pivotly secured'to the platform at 18 are a plurality of rockable levers '20 which extend upwardly from their respective pivot points 18 and tilt in vertical planes parall'eltothe path of movement of the platform 12in the guide frame members 10. At their upper ends the levers 20 areeach provided with a right angular portion '22 which is bifurcated to receive and journal a latch wheel 24, therein.

Spaced from tht pivot point 18 of each lever, I provide a clevi's 26 which is pivotly secured to the lever 20 and is also rigidly secured to the piston rod 28 of the prime mover 30' which is here seen to be a cylinder 32 having a longitudinally shiftable piston 34 to which the piston rod 28 is 'conn'ectedthrough'a conventional packing gland '36.

Extending from the cylinders 32 opposed to the piston rods 28, each fluid pressure motor 30 is provided with a rod 338 which is rigidly secured thereto. 'The rod extends through an aperture '40 formed in a bracket 42 which is welded or otherwise secured to the platform 12, and is thus journaled therein for rectilinear movement therethrough. At its outer end a stop nut and a lock not combination 44 is applied to the rod to limit its 'movementxin one direction through the bracket 42.

A strong co'mpression spring 4'6 encircles the rod '38 and applies expansion pressure between the bracket 42 'an'dthe'cylinder 32 of the fluid pressure motor or prime 'sequen'tily described) the spring 46 may compress forming a buffer spring or safety spring which will prevent distortion or breakage of parts, and yet it will be understood that the power of the compression spring 46 is such as to prevent accidental removal of the latch wheel 24 from the supporting socket or notch and therefore precludes accidental movement of the platform 12.

Each of the vertical guide posts is provided at each floor level with a notched cam plate 48. Midway its length the cam plate 48 is provided with the notch or socket 50 and at its ends 48 it is provided with bevels disposed at an obtuse angle with relation to the outer vertical edge face 52 of the cam plate 48.

Inspection of the drawing will show that the notch or socket 50 extends inwardly from the edge face 52 and the defining edges thereof are disposed at sixty degrees from the vertical or 30 degrees from the horizontal. This angle may vary a few degrees but it will be understood that since the movement of the platform is vertical, the angle of the notch defining edges is important to insure that the latch wheel 24 will effectively support the platform and yet will be provided with a means for compensating for a sufficient variation in platform position discrepancy to insure complete seating of the latch wheel 24 in the notch 50 in each instance.

The platform support pressure on the wheel 24 journal is vertical therefore, a reasonably flat notch defining face is presented tothe wheel to provide a maximum of supporting pressure without exerting undue horizontal pressure to the prime mover 30 holding the wheel 24 into the notch. Naturally, because of the angle there is some cam action, but this is not sufiicient to overcome the strength of the spring 46 or the prime mover or fluid pressure motor 30.

It will be noted that the fluid pressure motors are provided with a source of fluid under pressure P. This pressurized fluid is directed by means of a distributing valve V to each of the four motors 30 simultaneously so that they are all shifted to engage the latch wheels 24 in their respective notches 50 at one time. This pressure is supplied to the valve through a conduit such as 60 and from the valve to the several motors through conduits such as 62.

Vertical movement of the platform will be suflicient to drive the wheel 24 out of the notch 50 if it is so desired after the fluid pressure is relieved from the motor 30, however if it is desired that the wheels be withdrawn from the notches,' a second pressure line 64 may be applied to direct fluid under pressure to the cylinder in advance of the piston 34. Obviously, the valve will be one of the well known construction adapted to alternately pressurize and discharge at opposed ends of each cylinder.

It will be noted that the cam plate 48 is provided with a right angle lip 66 which has a plurality of vertically elongated openings 68 by means of which the cam plate is secured to a flange of the vertical guide post 10. Bolts 70 extend through the flange of the guide post 10 and through the elongated apertures 68 and by means of clamping nuts 72 releasably and adjustably secure the cam plates in the desired position.

Ears 74 are welded or otherwise secured to the guide posts and vertically disposed adjusting *bolts 76 are threadedly engaged through the ears and impinge against the upper and lower ends of the guide plate 48.

Lock nuts 78 are applied to the bolts 76 and the bolts are adapted to be rotated to accurately position the guide plate 48 in each instance before the cooperating bolts and nuts 70 and 72 are tightened. Obviously, then, the guide plates may be adjustably secured to insure proper leveling of the platform 12 at each of the plural horizontal plane levels at the delivery floors served by the elevator platform.

Having thus described my invention I claim:

1. In a vertically shiftable platform, means for leveling said platform at predetermined levels comprising a cam plate secured in a fixed position adjacent to the path of movement of said platform and having a socket; a latch wheel carried by said platform and moveable into and out of mating engagement with said socket; an axially reciprocal prime mover for alternately shifting said latch wheel into and out of mating engagement with said socket in accordance with manual selection; and resilient means urging said prime mover to a normal position effective to operate said latch Wheel and yieldable to admit of movement thereof when said latch wheel is held against movement in said socket.

2. In a vertically shiftable platform having a vertical guide frame provided with members disposed at the four corners of said platform, cam plates each having a socket and secured to each guide frame member for limited vertical adjustment; levers pivotally secured to said platform for tilting movement in vertical planes; latch wheels journaled at the ends of said levers and moveable thereby into and out of mating engagement with said sockets; axially reciprocal prime movers operably interconnected to said levers for alternately shifting said levers to selectively dispose said latch wheels in and removed from said sockets in accordance with manual selection; and resilient means urging said prime movers to a position effective to operate said levers and yieldable to admit of movement thereof when said latch wheels cannot move into said sockets.

3. In a vertically shiftable platform having a vertical guide frame provided with members disposed at the four corners of said platform, cam plates each having a socket and secured to each guide frame member for limited vertical adjustment; levers pivotally secured to said platform for tilting movement in vertical planes; latch wheels journaled at the ends of said levers and moveable thereby into and out of mating engagement with said sockets; fluid pressure motors operably interconnected to said levers and said platform for alternately shifting said latch wheels into and out of mating engagement with said sockets; buffer means yieldably holding said motors in operative position and yieldable to effect movement thereof when said latch wheels fail to seat in said sockets; and manually operable means for controlling operation of said fluid pressure motors.

4. In a vehicle parking elevator having a vertically shiftable platform moveable in a guide frame having vertical guide posts at the corners of said platform and notched cam plates secured to said platform at spaced predetermined vertical levels; means for securing said platform in a level position comprising levers pivotally secured to said platform for tilting movement in vertical planes; a latch wheel journaled at the end of each said lever and moveable thereby simultaneously into and out of mating engagement with the notch of said cam plates at one level; a fluid pressure motor having a cylinder, 21 cooperating piston and piston rod; the piston rod of each said fluid pressure motor being secured to a companion one of said levers for imparting said movement thereto; a rod secured to said fluid pressure motor and extend ing axially therefrom opposed to said piston rod; a bracket carried by said platform and rigidly secured thereto; said rod being journaled in said bracket for rectilinear movement and a compression spring encircling said rod and interposed between said bracket and said fluid pressure cylinder whereby to constitute a buffer spring to yieldably hold said latch wheels in said notches.

References Cited in the file of this patent UNITED STATES PATENTS 1,595,004 Haight Aug. 3, 1926 1,660,465 Withrow Feb. 28, 1928 1,773,163 Becker Aug. 19, 1930 

